aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/input/input-polldev.c
blob: 92b359894e81ed89d7608c90e4f52a2173daa8c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
/*
 * Generic implementation of a polled input device

 * Copyright (c) 2007 Dmitry Torokhov
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 */

#include <linux/jiffies.h>
#include <linux/mutex.h>
#include <linux/input-polldev.h>

MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
MODULE_DESCRIPTION("Generic implementation of a polled input device");
MODULE_LICENSE("GPL v2");
MODULE_VERSION("0.1");

static DEFINE_MUTEX(polldev_mutex);
static int polldev_users;
static struct workqueue_struct *polldev_wq;

static int input_polldev_start_workqueue(void)
{
	int retval;

	retval = mutex_lock_interruptible(&polldev_mutex);
	if (retval)
		return retval;

	if (!polldev_users) {
		polldev_wq = create_singlethread_workqueue("ipolldevd");
		if (!polldev_wq) {
			printk(KERN_ERR "input-polldev: failed to create "
				"ipolldevd workqueue\n");
			retval = -ENOMEM;
			goto out;
		}
	}

	polldev_users++;

 out:
	mutex_unlock(&polldev_mutex);
	return retval;
}

static void input_polldev_stop_workqueue(void)
{
	mutex_lock(&polldev_mutex);

	if (!--polldev_users)
		destroy_workqueue(polldev_wq);

	mutex_unlock(&polldev_mutex);
}

static void input_polled_device_work(struct work_struct *work)
{
	struct input_polled_dev *dev =
		container_of(work, struct input_polled_dev, work.work);

	dev->poll(dev);
	queue_delayed_work(polldev_wq, &dev->work,
			   msecs_to_jiffies(dev->poll_interval));
}

static int input_open_polled_device(struct input_dev *input)
{
	struct input_polled_dev *dev = input->private;
	int error;
	unsigned long ticks;

	error = input_polldev_start_workqueue();
	if (error)
		return error;

	if (dev->flush)
		dev->flush(dev);

	ticks = msecs_to_jiffies(dev->poll_interval);
	if (ticks >= HZ)
		ticks = round_jiffies(ticks);
	queue_delayed_work(polldev_wq, &dev->work, ticks);

	return 0;
}

static void input_close_polled_device(struct input_dev *input)
{
	struct input_polled_dev *dev = input->private;

	cancel_rearming_delayed_workqueue(polldev_wq, &dev->work);
	input_polldev_stop_workqueue();
}

/**
 * input_allocate_polled_device - allocated memory polled device
 *
 * The function allocates memory for a polled device and also
 * for an input device associated with this polled device.
 */
struct input_polled_dev *input_allocate_polled_device(void)
{
	struct input_polled_dev *dev;

	dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
	if (!dev)
		return NULL;

	dev->input = input_allocate_device();
	if (!dev->input) {
		kfree(dev);
		return NULL;
	}

	return dev;
}
EXPORT_SYMBOL(input_allocate_polled_device);

/**
 * input_free_polled_device - free memory allocated for polled device
 * @dev: device to free
 *
 * The function frees memory allocated for polling device and drops
 * reference to the associated input device (if present).
 */
void input_free_polled_device(struct input_polled_dev *dev)
{
	if (dev) {
		input_free_device(dev->input);
		kfree(dev);
	}
}
EXPORT_SYMBOL(input_free_polled_device);

/**
 * input_register_polled_device - register polled device
 * @dev: device to register
 *
 * The function registers previously initialized polled input device
 * with input layer. The device should be allocated with call to
 * input_allocate_polled_device(). Callers should also set up poll()
 * method and set up capabilities (id, name, phys, bits) of the
 * corresponing input_dev structure.
 */
int input_register_polled_device(struct input_polled_dev *dev)
{
	struct input_dev *input = dev->input;

	INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
	if (!dev->poll_interval)
		dev->poll_interval = 500;
	input->private = dev;
	input->open = input_open_polled_device;
	input->close = input_close_polled_device;

	return input_register_device(input);
}
EXPORT_SYMBOL(input_register_polled_device);

/**
 * input_unregister_polled_device - unregister polled device
 * @dev: device to unregister
 *
 * The function unregisters previously registered polled input
 * device from input layer. Polling is stopped and device is
 * ready to be freed with call to input_free_polled_device().
 * Callers should not attempt to access dev->input pointer
 * after calling this function.
 */
void input_unregister_polled_device(struct input_polled_dev *dev)
{
	input_unregister_device(dev->input);
	dev->input = NULL;
}
EXPORT_SYMBOL(input_unregister_polled_device);